Maou-sama no Machizukuri! ~Saikyou no Danjon wa Kindai Toshi~ - Volume 9 Chapter 18

When an S-class elite assassin-raised captain of a special ops suicide squad comes home from a high-stakes Africa mission, he finds himself offered something that could potentially set him up for life- a curious assignment that he could use to finally exit his days of war and slaughter.

Then placed into a high-school setting, Lin Yi is tasked by the chairman of a top-tier multi-billion company with bodyguard duty for non-other than his own daughter, a certain little Miss of said high-school.

His enemies, once ranging from drug lords, mafia bosses, political figures, and national leaders, are soon replaced with spoiled kids who happen to have rich papas and mamas, and Lin Yi finds his intense expertise and high-threat skillset misused, and very underwhelmed…

But he does get a harem cast as diverse as his old enemies, so Lin Yi decides that, for the sake of messing around with girls as an invincible entity in a down-leveled environment, leaving his bloody and death-filled war days behind is something he’d definitely want to strive for.

- Description from Novelupdates

Everything has to be studied to understand its meaning.

The traveler Chiba Shiroishi picked up a book called “The Will of Fire”.

When I opened it, the things on it had no nourishment, and the history of Konoha Village had no age, but the words ‘Will of Fire’ were written on every slanted page.

Shiraishi couldn’t sleep, so he took out the book “The Will of Fire” and read it carefully in the middle of the night, only to see the words in the cracks. The whole book was written with two words – pyramid selling!

Shiraishi felt hesitant and fearful for a while, and he decided that sooner or later, he must escape from this MLM brainwashing organization called Konoha!

(PS: Anime, Doujin, Naruto, Slow Heat, Not Brainless, Pseudo-Invincible)

- Description from novelbuddy

A 13-year-old deaf teenager living in the 21st century suddenly found himself as a young boy in Japan during the early 1900s. With two World Wars, two nuclear bombs, Hitler and many other disasters awaiting his future, he thought things couldn't get worse.Except it did.He found out later on that he had actually reincarnated into the world of Demon Slayer where man-eating demons ruled the night. He thought things couldn't get worse.Except it did.But hey! At least he had unparalleled talent, incredibly special eyes and future knowledge.How will the story of Demon Slayer change with the addition of this unique character? Will so many still die if the Hashiras had one more pillar in the final battle?Or will the story end on a much happier note?

Follow Chen Ming as he accepts disciples, establishes a sect, and fights his way in a world that deems him a cannon fodder.
He goes against any common sense using his wits and novel knowhow to finish missions and arm himself against his cruel fate.

- Description from Novelupdates